(1) Field of the Invention
The present invention relates to a cartridge for a typing ribbon and concerns more particularly a cartridge in which the supply reel has a flange provided with peripheral notches and having a ribbon tensioning lever and stop element engaging with the notches.
(2) Description of the Pior Art
U.S. Pat. No. A 4 810 839 discloses a cartridge for a typing ribbon comprising a container or casing for accommodating a supply reel having a flange provided on the outside edge with a series of peripheral notches and a tensioning and stop device comprising a tensioning lever which is pivoted on a pin on the container. The tensioning lever comprises at one end a pin, the lower part of which is co-operable with the series of peripheral notches on the flange of the supply reel while the upper part thereof guides and tensions the typing ribbon by the action of a spring which is applied to the other end of the lever and which is capable of holding the pin in engagement with the spaces between the series of notches, with the ribbon stationary, and which gives rise to a movement for engagement and disengagement as between the pin and the notches during the feed movement of the ribbon to hold it in a condition of tension in use thereof. The tensioning and stop device is sufficiently operational for typing ribbons which are fairly rigid and robust. On the other hand, since the lever is reasonably long, it is robust but heavy and, for optimum operation, the spring must also provide a fairly high level of tension for tensioning the ribbon. That device is therefore not suited for ribbons which have very thin deformable supports which are required when large amounts of ribbon are to be used in the cartridge.